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Bug 368600

Summary:	AIOOBE in OTJavaElement.getChildren()
Product:	[Tools] Objectteams	Reporter:	Stephan Herrmann <stephan.herrmann>
Component:	OTDT	Assignee:	Stephan Herrmann <stephan.herrmann>
Status:	VERIFIED FIXED	QA Contact:
Severity:	normal
Priority:	P3
Version:	2.1
Target Milestone:	2.1 M5
Hardware:	Other
OS:	Linux
Whiteboard:

Description Stephan Herrmann

2012-01-14 03:37:02 EST

I consistently get this exception when opening OT's CodeCompletionTest
in an editor:

java.lang.ArrayIndexOutOfBoundsException
	at java.lang.System.arraycopy(Native Method)
	at java.util.ArrayList.toArray(ArrayList.java:328)
	at org.eclipse.objectteams.otdt.internal.core.OTJavaElement.getChildren(OTJavaElement.java:96)
	at org.eclipse.objectteams.otdt.internal.core.RoleType.getMethodMappings(RoleType.java:106)
	at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:575)
	at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:609)
	at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.convert(SourceTypeConverter.java:186)
	at org.eclipse.jdt.internal.compiler.parser.SourceTypeConverter.buildCompilationUnit(SourceTypeConverter.java:109)
	at org.eclipse.jdt.internal.core.CompilationUnitProblemFinder.accept(CompilationUnitProblemFinder.java:121)
	at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.askForType(LookupEnvironment.java:235)
	at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:203)
	at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.findImport(CompilationUnitScope.java:710)
	at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.findSingleImport(CompilationUnitScope.java:764)
	at org.eclipse.jdt.internal.compiler.lookup.CompilationUnitScope.faultInImports(CompilationUnitScope.java:627)

Looking at the top frames this could mean two things: the list this.children
is corrupt, i.e., its elementData and size don't match or concurrent access
changes the length of the list while copying.

Comment 1 Stephan Herrmann

2012-01-14 03:53:14 EST

Against a corrupt ArrayList I can do nothing (would that be a bug in
the JRE??). I'm not fully convinced that concurrency was the root cause
because the issue was reproduceable while the workbench was running, but
disappeared when I restarted the workbench.

Anyway, I'm adding synchronization on this.children to prevent the
concurrency issue in this location. 

Released via commit 488052484e419c2f0486117ba4a6ccbbc31832bd

Comment 2 Stephan Herrmann

2012-01-14 04:14:39 EST

A google search confirms that other projects had concurrency issues
with ArrayList.toArray, too, e.g., bug 81675.

Comment 3 Stephan Herrmann

2012-09-22 15:52:01 EDT

Never seen again. Consider fixed.